Once thought that our love will for a long time,please forgive me,I can’t be with you till the end.

Once thought that our love will for a long time,please forgive me,I can’t be with you till the end.
Once thought that our love will for a long time,please forgive me,I can’t be with you till the end.

Once thought that our love will for a long time,please forgive me,I can’t be with you till the end.
我曾经以为我们的爱能天长地久,但请原谅我,我不能陪你到走到最后/直到永久.

曾经以为我们的爱会在很长一段时间,请原谅我,我不能陪你到永远

曾以为我们的爱会到永远,请原谅我,我不能陪你走到最后了

我试试:
曾经以为我们的爱情能够持续很久,但是请原谅我,我不能陪你到最后了