Praise be to Allah.
Yes, it is part of the belief of the Muslims and one of the pillars of their religion to believe in all the Prophet and Messengers of Allah – may the blessings and peace of Allah be upon them – as Allah, may He be exalted, says:
“Say (O Muslims): We believe in Allah and that which has been sent down to us and that which has been sent down to Ibrahim (Abraham), Ismail (Ishmael), Ishaque (Isaac), Yaqoob (Jacob), and to Al-Asbat (the twelve sons of Yaqoob (Jacob)), and that which has been given to Moosa (Moses) and ‘Eesa (Jesus), and that which has been given to the Prophets from their Lord. We make no distinction between any of them, and to Him we have submitted (in Islam).”
“The Messenger (Muhammad ) believes in what has been sent down to him from his Lord, and (so do) the believers. Each one believes in Allah, His Angels, His Books, and His Messengers. They say: We make no distinction between one another of His Messengers - and they say: We hear, and we obey. (We seek) Your Forgiveness, our Lord, and to You is the return (of all).”
Believing in all the Prophets means loving them, respecting them, venerating them and acknowledging their virtue.
But this phrase that you mention, “I love Jesus”, is something that belongs exclusively to the Christians and has become a slogan or symbol for them, because Jesus (Yasoo‘ in Arabic) is the name that the Christians give to the Prophet of Allah ‘Eesa (peace be upon him).
They distorted the name ‘Eesa to Yasoo‘, just as they distorted the name Yahya to Yohanna (John), Yoonus to Yoonaan (Jonah) and Maryam to Mary.
There is nothing in the words of Allah, may He be exalted, or in the words of His Messenger (blessings and peace of Allah be upon him) or in the words of his Companions (may Allah be pleased with them), indeed we do not know of anything in the words of any of the scholars of Ahl as-Sunnah in which the name Yasoo‘ (Jesus) is used to refer to the Prophet of Allah ‘Eesa (peace be upon him). Rather the names that are used are “ ‘Eesa” or “al-Maseeh (the Messiah).”
The Muslims say: We believe in ‘Eesa (peace be upon him) and we love him, and we seek to draw close to Allah, may He be exalted, by loving him. But we do not say as these people say who have distorted the religion of Allah and changed the words of Allah, “We believe in Yasoo‘ (Jesus) and love him.”
Similarly, the word “Yasoo‘” for the Christians means “The Redeemer”, and they believe that their religion that they follow is the religion of redemption. So the name Yasoo‘ and its meaning is connected to their false beliefs. Hence it is not permissible to imitate them in that.
The Messiah ‘Eesa ibn Maryam is the Prophet of Allah and His Messenger in whom we believe, and we believe that he foretold the coming of our Prophet Muhammad (blessings and peace of Allah be upon him); he is not “Yasoo‘ the Redeemer, the son of God, the third of three” in whom the Christians believe.
The phrase that you mention refers to the latter and is a slogan for a religion of kufr. For this reason it is not allowed and it is not permissible for a Muslim to write it or to wear a garment on which it is written.
For more information on imitating the kuffaar, please see the answer to question no. 69789.
And Allah knows best.